1. Field of the Invention
The invention relates to surgical apparatus and, more particularly, to an electrode lead and insertion assembly for positioning a tissue stimulating electrode in electrical contact with living tissue which is to be stimulated,
2. Brief Description of the Prior Art
Electrical stimulation of living tissue has previously produced beneficial therapeutic results ranging from stimulation of heart function to relief of severe pain states which are unresponsive to more conventional treatment. Implantable electrode leads have come into use which can be positioned in contact with tissue to be stimulated without the need for major surgery, the usually flexible electrode leads being carried by hollow rigid insertion needles which penetrate the skin and body wall to a suitable depth. The flexible electrode lead is then fed into a desired position relative to the tissue which is to be stimulated through the inserted needle, the needle then being withdrawn from the body over the entire length of the electrode lead while maintaining the lead in the desired position within the body. In such prior systems, the anterior end of the electrode lead could not be fitted with electrical connections or electrical components which could not be drawn through the hollow needle. In prior practice, it is therefore necessary for the surgeon to attach or form electrical connections to the electrode lead after the needle is pulled from the anterior end of the lead. Such connections, made under operating room conditions by medical personnel, are time consuming and often not comparable to the quality of electrical connections made under more controlled manufacturing conditions. The invention thus provides, among other things, the capability of implanting an electrode lead through the skin, which lead has electrical connections at its anterior end which are too large to pass through surgical insertion needles. Electrode leads which are pre-fabricated and/or connected to electrostimulation devices prior to implantation can therefore be conveniently used with substantial savings of time and with greater reliability than has previously been possible.